Method of making nozzles for spinning fibers



Jan. 20, 1970 A. KEIL ETAL 3,491,181

METHOD OF MAKING NOZZLES FOR SPINNING FIBERS Original Filed Aug. 20, 1965 INVENTORS ALFRED KEIL HEINZ MALLY ADOLF WOLFL HANS GRUHL United States Patent 3,491,181 METHOD OF MAKING NOZZLES FOR SPINNING FEBERS Alfred Keil, Wolfen, Kreis, Bitterfeld, Heinz Mally, Dresden, and Hans Gruhl and Adolf Wolfl, Pirna, Germany, assignors to VEB Sachsisches Kunstseidenwerk Siegfried Radel, Pirna, Germany Original application Aug. 20, 1965, Ser. No. 481,371, now Patent No. 3,357,047, dated Dec. 12, 1967. Divided and this application July 20, 1967, Ser. No. 671,172 Int. Cl. C22c 5/00; D0111 3/00; B29c 1/02 U.S. Cl. 264-219 3 Claims This is a divisional application of copending application Ser. No. 481,371, filed Aug. 20, I965, now US. Patent No. 3,357,047.

The present invention relates to a nozzle for spinning synthetic fibers and to a method for manufacturing such a nozzle. The nozzle according to the invention is particularly suited for spinning fibers of regenerated cellulose.

Spinning nozzles previously made solely from noble metals, preferably gold and platinum, have proved suitable for the spinning of fibers from regenerated cellulose, and they are practically the only ones used for that purpose.

It was also known to use spinning nozzles consisting of non-metallic materials, such as polyamide, polyvinyl chloride, porcelain, glass, and the like. These nozzles, however, have many shortcomings regarding the chemical and mechanical resistances. For example, these spinning nozzles especially those made from the non-metallic materials mentioned above, are damaged and decompose during the necessary cleaning process with warm chlorosulturic acid. The channels of the nozzle aperture of the plastic nozzles are especially unsatisfactory as far as their mechanical resistance is concerned. The channels are heavily damaged within a short period of time so that the nozzles have to be removed. The known nozzles have shortcomings in other respects, too. For example, the manufacture of porcelain and glass nozzles is very costly. For the above mentioned reasons, many attempts have been made to eliminate the difficulties caused by plastic, porcelain and other non-metallic nozzles. One attempt consisted in providing a combined nozzle in which the body that had previously been made of a noble metal, was made from one of the above mentioned non-metallic materials, and the nozzle bottom carrying the nozzle aperturc channels (spinning apertures) was made of a noble metal alloy of a known composition eg of gold/ platinum, platinum/rhodium, or the like. The nozzle bottom, after completion of the nozzle body, is pressed into and/or glued into a ring groove applied to the nozzle body. However, the nozzles made in this manner were not satisfactory in the spinning of synthetic fibers due to the lack of a firm connection between the nozzle bottom and the nozzle body.

It is the object of this invention to provide an improved spinning nozzle for synthetic fiber spinning, said nozzle having higher chemical and mechanical stability.

It is also the object of this invention to provide a spinning nozzle in which the nozzie body comprises a plastic material or a plastic containing an additive, and a nozzle bottom comprising a noble metal which is resistant to chemical and mechanical influences present during the spinning process of synthetic fibers, particularly those from regenerated cellulose.

It is yet another object of the invention to provide a method for establishing a firm connection between the body and the bottom portion of the nozzle according to the invention.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawing.

3,491,181 Patented Jan. 20, 1970 The nozzle according to the invention consists of a composite body and bottom portion, the body being made of an especially suited plastic material and the apertured bottom portion being made of a noble metal or noble metal alloy, said portions being firmly connected to one another in a manner which permits them to be subjected to any pressure obtaining during the spinning process and to the cleaning of the nozzle, without damaging the connection between the component nozzle parts.

Tests with a number of thermo-plastic materials have shown that polychloro-fluoro-ethylene derivatives, are especially suitable as plastic material in the manufacture of the spinning nozzles of this invention. These compounds may be represented by the formula iiii tail,

wherein X is partly substituted by fiurine and partly by chlorine. Polyethylene, on the other hand, does not meet with the chemical requirements. The most suitable material for this die extrusion method is polymonochlorotrifiuoroethylene.

A firm connection between the nozzle body consisting of polychloro-fluoroethylene derivatives, and the nozzle bottom consisting of a noble metal is obtained by mounting the nozzle bottom into the body during the manufacture of the body.

In a special embodiment of the invention the channels in the perforations are bored into the nozzle bottom prior to inserting it into the nozzle body. The channels are filled with a temperature-resistant mass which is chemically removed after the manufacture of the nozzle has been completed. The temperature-resistant mass is enamel, which can be removed by means of an acid or an alkaline solution.

The required positioning or seating of the nozzle bottom into the nozzle body may be achieved in various ways. The nozzle bottom may, for instance, have a flat surface for contact with the body portion; or the bottom portion of the nozzle may be of a shape with the rim pulled up, bent at right angles or flanged. The edge of the bottom is preferably provided with holes of various shapes to improve the positioning or seating.

The invention will now be more fully described with reference to the accompanying drawings in which:

FIG. 1a shows a complete nozzle with a nozzle body of cylindrical shape and a nozzle bottom inserted therein;

FIG. 1b shows another nozzle body of conical shape Without the nozzle bottom attached;

FIGS. 2a to d show cross-sectional views of various examples of nozzle bottoms, and

FIG. 3 is a top view of a nozzle bottom with four holes.

Referring now to FIGS. 1a and 112, these illustrate two different shapes of the body portion of the nozzle according to the invention. FIG. 1a shows a cylindrical body 10 with a straight wall portion 12 to be connected with a bottom, and a flange 14 for connection with the spinning device (not shown). The bottom portion is shown at 16; it has a flat perforated plate 18 which serves as nozzle proper for the extrusion of the spinning solution, and a bent-back portion 20 with crimped edge for engagement with the end of wall 12 of the nozzle body.

FIG. lb illustrates a different shape of a nozzle body 22, which is conical. In this embodiment, too, one end of the nozzle wall 24 is flanged, the other is flat for receiving a fiat bottom, as shown, for instance in FIG. 2a.

FIGS. 2a to 2b show different shapes of nozzle bottoms. FIG. 2a illustrates, as mentioned above, a flat, plateshaped bottom 24, with a plurality of perforations 26a. FIG. 2b is a cup-shaped nozzle bottom 28 with perforations 26b. FIG. 2c is a bottom in the shape of a flanged cup 30, likewise having perforations 26c and FIG. 2d illustrates a bottom portion 32 similar to the one shown in FIG. 1a in assembled position the bottom portion has perforations 26d.

FIG. 3 is a top view of the bottom portion which is designated by 34, having a rim 36 which is provided with holes 38. During the process of manufacuring the nozzle, these holes are filled with plastic which serves for the connection of the body and the bottom portion in the finished nozzle, as later described. While the holes shown in FIG. 3 are circular, it should be understood that they could have any desired shape, e.g. square, triangular or oval.

In the following, the method for manufacturing this nozzle will now be described in further detail.

The nozzle body is given an appropriate shape in a thermo-plastic process under high pressure, with a nozzle bottom being positioned in a suitable manner in the body, or attached thereto, respectively. For a successful molding operation it is advisable not to raise the temperature too far beyond the melting point of the plastic material, as decomposition may occur later as a result of the excessive heating, thus unfavorably influencing the durability of the nozzle body. On the other hand, flowing of the plastic material will not occur at temperatures slightly below the melting pointdespite high pressure. It is important to provide the nozzle bottom with the nozzle apertures 26 a to d and to polish the bottom prior to its insertion into or attachment to the nozzle body. The mass with which the channels of the nozzle perforations 26a26d are filled during the polishing process is applied to the nozzle bottom at a high temperature, which would damage the plastic material of the nozzle body. The fill ing substance is removed chemically from the nozzle apertures by acid or caustic alkali only after the completion of the nozzle so that the channels cannot be clogged with melted plastic material during the injection or pressing in of the nozzle bottom into the nozzle body.

The rigid connection of the nozzle body and the nozzle bottom is improved by the arrangement of holes 38 at the rim of the nozzle bottom which may have various shapes as mentioned. The plastic material flows into these holes during the thermo-plastic process and thus provides a firm connection between nozzle body and nozzle bottom.

As has been found in large scale tests the nozzle body consisting of polychloro-fluoro-ethylene, particularly polymonochloro-trifluoro-ethylene, has considerable advantages over that consisting of polyamides, polyvinyl chloride, and the like, which have been used up to now and especially with respect to the chemical requirements during the spinning process. The plastic mentioned is resistant to spinning bath temperatures up to 70 C., sulphuric acid,

carbon sulphide and warm chloro-sulphuric acid. It has not been possible to detach or loosen the nozzle bottom inserted into the nozzle body according to this invention at pressures far exceeding 11 atmospheres so that the advantage of the nozzle made according to the present invention is obvious in view of its resistance to chemical attack and the high durability.

While in the foregoing the invention was described for the body portion of the nozzle consisting of plastic as defined, it should be understood that plastic may be used very successfully, which contains additives of materials conventional in this art. Such materials are for instance, metallic oxides.

What we claim is:

1. A method for the manufacture of a composite nozzle for spinning synthetic fibers, said nozzle having a body portion consisting of a polymer material having the general formula wherein X is partly substituted by fluorine and partly by chlorine and a bottom portion made of a metallic material selected from the group consisting of noble metals and noble metal alloys, said body portion consisting of a walled shell with the rim of the bottom portion embedded in said wall, said method comprising boring channel-shaped apertures into the nozzle bottom, filling said apertures with a temperature resisting mass, inserting the nozzle bottom into the nozzle body at a temperature slightly above the melting point of said polymer material, cooling the thus formed composite nozzle down to normal temperature, and removing the mass filled into the chan- References Cited S.N. 349,256 to Aschenbrenner et al. Published Apr.

'27, 1943, by ARC.

DONALD J. ARNOLD, Primary Examiner A. H. KOECKERT, Assistant Examiner US. Cl. X.R. 

1. A METHOD FOR THE MANUFACTURE OF A COMPOSITE NOZZLE FOR SPINNING SYNTHETIC FIBERS, SAID NOZZLE HAVING A BODY PORTION CONSISTING OF A POLYMER MATERIAL HAVING THE GENERAL FORMULA -(C(-X)2)4WHEREIN X IS PARTLY SUBSTITUTED BY FLUORINE AND PARTLY BY CHLORINE AND A BOTTOM PORTION MADE OF A METALLIC MATERIAL SELECTED FROM THE GROUP CONSISTING OF NOBLE METALS AND NOBLE METAL ALLOYS, SAID BODY PORTION CONSISTING OF A WALLED SHELL WITH THE RIM OF THE BOTTOM PORTION EMBEDDED IN SAID WALL, SAID METHOD COMPRISING BORING CHANNEL-SHAPED APERTURES INTO THE NOZZLE BOTTOM, FILLING SAID APERTURES WITH A TEMPERATURE RESISTING MASS, INSERTING THE NOZZLE BOTTOM INTO THE NOZZLE BODY AT A TEMPERATURE SLIGHTLY ABOVE THE MELTING POINT OF SAID POLYMER MATERIAL, COOLING THE THUS FORMED COMPOSITE NOZZLE DOWN TO NORMAL TEMPERATURE, AND REMOVING THE MASS FILLED INTO THE CHANNELS OF THE NOZZLE HOLESS WITH A CHEMICAL AGENT DISSOLVING SAID MASS. 